Telephone system



10, 1933- e. c. HAWKINS ET AL 9,4

. TELEPHONE SYSTEM Filed July 20, 1932 C-Jeacge CC Hawk/n5 Ja fiep/y CZ 7 04/19/0 ZzoneZ R fiQedZ/ INVENTOR l lu l BY ATTOR N EY Patented Oct. 10, 1933 PATENT OFFICE 1,929,422 TELEPHONE SYSTEM George 0. Hawkins and Joseph G. 'Pomeroy, United States Navy, and Lionel It. Fiedler,

Washington, D. 0;

Application July 20, 1932. Serial No. 623,678

6 Claims.

(Granted under the act of March a, 1883, as

amended April 30, 1928; 370 0. G. 757) This invention relates to telephone systems,

and more particularly to a fully metallic tele-.

phone system of the central battery supply type wherein various telephone sets may be connected together, either by plugging in of telephone sets at station jack boxes remotely located from and connected to a central control switch board, or

the telephone sets already connected into the circuit at the remote station jack boxes can be connected or disconnected from the common talking and supply circuit at will by means of switches on the central control switch board.

One of the objects of the present invention is to provide a means for keeping the battery currents of each telephone transmitter at a fixed normal value irrespective of open circuits, short circuits or grounds on any other individual line or lines connecting the telephones or jack boxes to the central control switch board.

A further object of this invention is to provide a telephone system wherein the efiiciency of the speed frequency transmission characteristics of the system cannot be appreciably reduced by a short circuit on one or more of the lines or circuits connecting the remote telephone sets to the centrally located control switch board, it being understood that only the telephone set or sets connected to the jack box or boxes the lines of which are short circuited are rendered inoperative, the remaining telephone sets connected to the system functioning in their normal manner.

A further object of thisinvention is to provide a telephone system wherein compensating resistances and reactances usually used in such a system and installed at the individual remote stations are dispensed with, thus materially simplifying the individual station equipment and still providing a system ,wherein the emciency of speech transmission is not materially eifected by a variation within suitable limits of the number of telephone setsconnected to the system.

A further object of this invention is to'provide a telephone system of the central battery supply central control switch board type wherein two separate and distinct bus circuits are provided on the centralcontrol switch board, one a common current supply bus and the other a common'talking circuit bus, the individual lines to the remote telephone station jack boxes to be connected through suitable impedance coils to the common current supply bus and to the common talking circuit bus through suitable capacities, provision being made by switches so that the outgoing lines on the switch board can be connected or disconnected from these common buses at will.

A further object of this invention is to' provide a central battery'supply central control switch board type of telephone system in which two or more telephone sets can be selectively connected through a single circuit or pair oi telephone conductors at jack boxes remotely located from the central control switch boardso that such telephones can function inthe intended manner without causing any appreciable loss in in efficiency of transmission to or fromthe telephone sets so connected to the single circuit and to or from any other telephone set connected to the system. v

A further object of this invention is to provide a telephone system wherein it is possible to connect by means of manually operated selective switches any telephone at willto any one or all of the telephones in the system.

A further object of this invention is to provide a switch board with a single common current supply circuit bus, a plurality of common talking circuit buses and a plurality of bus line disconnect switches, talking bus cross connecting switches and line telephone jacks allso wired and connected that: 7

(a) Any group of telephone sets normally connected to one talking circuit bus can be con,- nected to any other group of telephone sets normally connected to a second talking circuit bus by means of cross connecting switches. a

(b) Any individual telephone set normally connected to one common talking circuit bus can other individual telephone set normally connected to the same talking bus or to any other talking bus so thata conversation can be carried on between the two individual telephone sets so connected by a patching cord without interfering with separate conversations being carried on simultaneously between the remaining telephones normally connected to the talking bus or buses mentioned.

(c) Any individual telephone normally connected to one common talking bus can by means of suitable, patching cords and talking bus line switches be connected to any group of telephones normally connected to a second talking bus so that in effect the individual telephone forms a part of a group oftelephones connected to the second talking bus and so that a conversation can be carried on between the telephones normally or effectively connected to the second bus without interfering with the conversation being carried on simultaneously between telephones remaining normally connected to the first talking bus.

With the above and other objects in view, the invention consists in the construction, combination and arrangement of parts as will be described more fully hereinafter.

These and other features not specifically mentioned above will more clearly appear from the following specification and the accompanying drawing-which illustrates diagrammatically one form of the invention.

In the accompanying drawing wherein like parts are identified by like reference characters, lines A, B, C, and D are shown as representative of a large number of lines equipped with substation jack boxes extending from a central switch board 18. The common current supply bus 2-3 located on the central control switch board 18 is supplied with suitable potential by source 1, such as a storage battery or direct current generator. The individual telephone sets 20 are connected through the jack boxes 16, lines A, B, etc., through the impedances 26 and 27 and the switch 24 to the common current'supply bus 2-3. The individual telephone sets 20 are further connected in like manner through the lines A, B, etc., through the capacities 28 and 29 and talking bus line disconnect switches 25 to the common talking bus or buses 4-5, 6-7, 8-9 or 10-11. The individual telephones are also connected in like manner through capacities 28, 29 to the patching jacks 30. The common talking buses are each provided with a number of cross connecting switches 12 by means of which any two or more of the common talking buses may be connected to any one of the cross connecting buses 13, 14, or 15.

The present system may be best explained by comparison with a telephone system of a more or less usual type as exemplified in the patent to Edwards No. 1,293,060, patented February 4, 1919. In case of a short circuit on any one of the lines such as A and B of Edwards, .a path of low resistance is afforded for the flow of all current through the impedances 11 and 12 so that the potential across the usual talking bus is considerably reduced, if not reduced to zero.

Hence, it follows that the current through telephone set transmitters connected to lines 0 and D is reduced to such an extent that it is impossible to carry on a conversation between telephones connected to lines C and D.

Referring now to the drawing of the instant application, it will be noted that a short circuit on any line or lines, such as A and B, has no appreciable effect on the direct current flowing through the telephone set transmitters connected to lines C and D. In the Edwards device a short circuit on any line results in a complete interruption of conversation, on all telephone sets connected to the same talking bus as that line, while a similar short circuit on any line of the system herein disclosed results in no interruption of conversation between the phones connected to the common bus 4-5 other than on the telephone connected to the line or lines so short circuited.

It has been explained that a short circuit on any line, such as A of Edwards, acted in effect as a short circuit on the talking bus connected thereto, thus reducing the supply of potential across this bus to zero. It is therefore apparent that with a short circuiting on the talking circuit bus, no speech current can be generated on or transmitted to or received from this bus by any telephone set connected thereto. On the other hand, a short circuit on any line, such as A of the present disclosure, results in no short circuit on the talking bus, but rather results in the bridging of capacities 28 and 29 of line A across the'talking bus 4-5. This capacity bridge across the talking bus has no appreciable effect on the talking current transmitted to the bus 4-5 where the capacities; 28-29 are made of proper value. Thus, the proper functioning of the telephones connected to bus 4-5 other than the telephone connected to the short circuited line A is not appreciably effected;

In the present system it is possible to have two normally independent groups of telephones connected through their independent talking buses and cross connecting switches and buses so that any group of telephones can be connected at will to form an effective part of any othergroup of telephones. Thus, if it is desired that the phones connected to the common talking bus 4-5 be effectively connected to the phones normallyconnected to bus 6-7, the cross connecting switch 12 connected to bus 4-5 and the cross connecting bus 13 is closed. Likewise, the cross connecting switch 12 connected to talking bus 6-7 and to cross connecting bus 13 is closed. Then in effect, buses 4-5' and 6-7 form a common talking bus and all phones connected to these buses may be used to carry on a common conversation or all but two'of the phones on these buses may be' disconnected so that a single conversation may be carried on between any two of the phones on these buses.

Suppose it is desired that the telephone A normally connected to the talking bus 4-5 be made to form a part of the group connected to talking bus 6-7, the talking bus line switch 25 connected to line A is open. One plug 31 of the patch cord 32 is inserted in the jack 30 of line A, the other plug 31 of the cord is inserted in the jack 30 of any line C or D which is normally connected to bus 6-7. Then all phones connected to talking bus 4-5 except the phone" on line A can be used to carry on a conversation while the phone on line A and all other phones connected to bus 6-7 can be used to carry on a separate conversation simultaneously. 7

In case it is desired to carry on a conversation between two stations each normally connected to independent groups such as beteween telephones on line A of bus 4-5 group and on line B of bus 6-7 group, and still permit simultaneous use in: dependently of all the remaining phones on bus 4-5 and on bus 6-7 group, it is only necessary to open the talking bus line'switches 25 on lines A and B and insert the-plugs 31 of the patching cord 32 in the jacks 30 connected to lines A and B, thus making it possible to carry on independent conversations. 2

Line B is shown as having two jack boxes 16 connected thereto, while line E may be connected by means of doublepole double throw switch 17 to either of lines B or C. It is to be understood that other or additional jack boxes may be connected to the remaining lines where it is desired that two or more phones be connected together continuously.

It will be understood that the above description and accompanying drawing comprehend only the general and preferred embodiment of our invention, and that various changes in construction, proportion and arrangement of parts may be made within the scope of the appended claims without sacrificing any of the advantages of this invention.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment. of any royalty thereon.

What we claim is:

1. In a telephone system of the central battery supply, central control switchboard type, a common current supply bus, a plurality of lines, switches individual to each of said lines for connecting said lines to said current supply bus, reactance coils connected in circuit between said lines and said switches, a plurality of talking buses each common to a plurality of lines, talking current switches individual to each of said lines for connecting said lines to the associated common talking buses, capacities connected in circuit between said lines and said talking current switches, and patching jacks connected to the talking current switches whereby a talking connection may be made to any line either via the talking current switch and its associated common talking bus or via the patching jack and its patching cord and plug or both.

2. In a telephone system of the central control switchboard type, a common currentsupply bus, a plurality of lines, impedance means connecting the wires of said lines to the current supply bus, a plurality of talking buses each common to a plurality of lines, a plurality of cross connecting talking buses, means for selectively connecting said common talking buses to said cross connecting buses, means for selectively connecting said common talking buses to the lines individual thereto, means connected between the last named means and the lines associated therewith for preventing the ilow of direct current to the talking buses while permitting the flow of alternating current speech components thereover.

3. In a telephone system, a common current supply bus, a plurality of lines, impedance means connecting said lines to the current supply bus, a plurality of primary speech current buses each common to a plurality of lines, a plurality of secondary speech current buses each common to said primary speech current buses, means for selectively connecting said secondary speech current buses to said primary speech current buses, means for selectively connecting said primary speech current buses to the lines individual thereto, and means for preventing a short circuit condition on any line from seriously affecting the speech current transmission characteristics of any buses operatively connected to said line, said last mentioned means comprising condensers connected between said lines and the means for selectively connecting said lines to the primary speech current buses.

4. In a telephone system, a common current supply bus, a plurality of lines, impedance means connecting said lines to the current supply bus, a plurality of primary speech current buses each common to a plurality of lines, a plurality of secondary speech current buses each common to said primary speech current'buses, means for selectively connecting said secondary speech current buses to said primary speech current buses, means for selectively connecting said primary speech current buses to the lines individual thereto, means for preventing a short circuit condition on any line from seriously afiecting the speech current transmission characteristics of any buses operatively connected to said line, said last mentioned means comprising condensers connected between said lines and means for selectively connecting said lines to the primary speech current buses and means for connecting two or more telephone sets to a single line.

5. In a telephone system of the central battery supply, central control switchboard type, a common. current supply bus, a plurality of lines, switches individual to each of said lines for connecting said lines to said current supply bus, reactance coils connected in circuit between said 100 lines and said switches, a plurality of talking buses each common to a plurality of lines, talking ourrent switches individual to each of said lines for connecting said lines to the associated common 7 talking buses, capacities connected in circuit be- 1 5 tween said lines and said talking current switches, patching jacks connected to the talking current switches whereby a talking connection may be made to any line either via the talking current switch and its associated common talking bus or via the patching jack and its patching cord and plug or both, and means for connecting two or more telephone sets toa single line.

6. In a telephone system, a common current supply bus, a plurality of lines, impedance means connecting said lines to the current supply bus, a plurality of primary speech current buses each common to a plurality of lines, a plurality of secondary speech current buses each common to said primary speech current buses, means for selectively connecting said secondary speech current buses to said primary speech currentbuses, means for selectively connecting said primary speech current buses to the lines individual thereto, patching jacks connected to said lines whereby a connection may be made to any line either via the jack or the speech current buses, and means comprising condensers connected in circuit be: tween said lines and said jacks for preventing a short circuit condition on one line from seriously afiecting the speech current transmission characteristics of any other line connected to said first line via its associated patching jack.

GEORGE C. HAWKINS. 

